It is well known in the art of shared bus systems, such as the Mitel.RTM. Open Telephony Platform System, that a backplane clock signal may be driven by any circuit card installed in the backplane of the system. In most cases, more than one installed card may be capable of driving the clock signal. Moreover, it may be necessary to transfer control of the backplane clock signal from a first card to a second card while the shared bus system is operational. This necessitates an interruption-free handover of control of the clock signal from the first card driving the clock signal to the second card.